Both blades had some light surface rust, so I polished them and applied grease to prevent further rusting. The blades themselves show no signs of deterioration. They can be used with current models. - Brand: CARL - Model Name: K-28 Round Blade - Model Name: K-29 Perforating Blade - Type: Disc Cutter Replacement Blades - Quantity: 1 each Thank you for looking.